The major aim of this project is to create mouse genetic mutants for genes which likely play a role in craniofacial development and which may be involved in the etiology of human craniofacial defects. The genes (H6, LD71) have been isolated from a human embryonic craniofacial-specific library (Project 3), and additional genes are being isolated by genetic linkage analysis (Project 2). We will create both loss-of-function (gene knock-out) and gain-of-function (embryonic ectopic expression) genetic mutations in mice using transgenic technologies. These experiments will give direct evidence for the role these genes play in craniofacial development as well as providing mouse models of human disorders. We will also identify the DNA regulatory regions of these genes which control their craniofacial-specific expression during embryogenesis using the LacZ gene as a marker in transgenic mice.